Effect of Third Elements on Pseudoelastic Behavior in Fe3Al Single Crystals

Abstract

The pseudoelastic behavior of Fe3Al single crystals doped with an extra element (e.g. Ti, V,
Cr, Mn, Co, Ni, Si, Ga, Ge) was investigated. In binary Fe-23.0at.%Al crystals with the D03 structure,
1/4[111] superpartial dislocations moved independently dragging the nearest-neighbor anti-phase
boundaries (NNAPB) during loading. During unloading, the NNAPB pulled back the superpartials
decreasing its energy resulting in a giant pseudoelasticity of which the recoverable strain is about 5 %.
Addition of a third element significantly affected the pseudoelastic behavior of Fe3Al single crystals.
Mn- or Ga-doped crystal demonstrated a giant pseudoelasticity. In particular, Ga-doping was found to
be effective in the enhancement of the pseudoelasticity. On the other hand, the amount of strain
recovery decreased upon doping of the other elements. The frictional stress of the superpartials, the
back stress of the NNAPB and ordered domain structure in the crystals changed upon doping, which
was closely related to the pseudoelastic behavior.